<template>
	<!-- 渐隐渐现效果 -->
	<div>
		<router-link 
			tag="div" 
			to="/" 
			class="header-abs"
			v-show="showAbs"
			>
			<div class='iconfont header-abs-back'>&#xe600;</div>
		</router-link>
		<div 
			class="header-fixed" 
			v-show="!showAbs"
			:style="opacityStyle"
			>
			景点详情
			<router-link to="/">
				<div class='iconfont header-fixed-back'>&#xe600;</div>
			</router-link>
		</div>
	</div>
</template>

<script>
	export default {
		name: 'DetailHeader',
		data () {
			return {
				showAbs:true,
				opacityStyle: {
					opacity: 0
				}
			}
		},methods: {
			handleScroll () {
				const top = document.documentElement.scrollTop
				if (top > 60 ) {
					let opacity = top / 140
					opacity = opacity > 1 ? 1 : opacity
					this.opacityStyle = { opacity }
					this.showAbs = false
				} else {
					this.showAbs = true
				}
			}
		},
		activated () {
			window.addEventListener('scroll',this.handleScroll)
		},
		deactivated () {
			window.removeEventListener('scroll',this.handleScroll)
		}
	}
</script>

<style >
	.header-abs {
		position: absolute;
		left: .2rem;
		top: .2rem;
		width: .8rem;
		height: .8rem;
		line-height: .8rem;
		border-radius: .4rem;
		text-align: center;
		background: rgba(0, 0, 0, .8);
	}

	.header-abs-back {
		color: #fff;
		font-size: .4rem;
	}

	.header-fixed {
		z-index: 2;
		position: fixed;
		top: 0;
		left: 0;
		right: 0;
		height: .86rem;
		line-height: .86rem;
		text-align: center;
		color: #fff;
		background: #00bcd4;
		font-size: .32rem;
	}

	.header-fixed-back {
		position: absolute;
		width: .64rem;
		text-align: center;
		font-size: .4rem;
		top: 0;
		left: 0;
		padding-left: .1rem;
		color: #fff;
	}
</style>
